Apparatus for governing duplex-machine drivers



June 24, 1930. SCHMTZER 1,766,548

APPARATUS FOR GOVERNING DUPLEX MACHINE DRIVERS Filed April 15. 1927 nit/716 Mad;

Patented June 24, 1930 UNITED STATES PATENT. OFFICE RICHARD scnm'rznn, or ZURICH, SWITZERLAND, ASSIGNOR T AKTIENGESELLSCHAFT BROWN BOVERI & cm, 015' BADEN, SWITZERLAND, A JOINT-STOCK COMPANY or SWITZERLAND APPARATUS FOR GOVERNING DUPLEX-MAEHINE DRIVERS Application filed April 13, 1927, Serial No. 183,305, and in Germany April 26, 1926.

' of the driven machines, in such fashion as to obtain maximum efficiency of performance.

Another object isthe provision of a method for governing the operation of a prime mover and the load imposed thereon by oneof a plurality of machines driven thereby, in such fashion as to maintain constant the, performance of another driven by the prime mover.

Another object is the provision of apparatus whereby the governing of a. prime mover, in the manners above specified, may be accomplished automatically.

Another object is the provision of apparatus for automatically governing the feed ofwork to one machine driven by a prime mover, and at the, same time, governing the prime mover, in such fashion as to maintain constant the performance of another machine driven by the prime mover.

machine will be pointed out or indicated hereinafter,

or will appear to one skilled in the art upon an. understanding of the invention or its employment in use.

In the drawings forming a part of this specification, I illustrate certain arrangements of apparatus wherein the invention may be embodied and practiced, but it is to be understand that these are here presented for purpose of illustration only and are not to be accorded any interpretation calculated to limit the claims short of the true and most comprehensive scope of the lIIVGHtlOIl in the art. 7

In sald drawings, .,Fig. 1 1s a schematic representation of an assembly of apparatus including a driving turbine, a generator and a wood grinder driven by .the turbine, together with governing apparatus for controlling feed of Other and further objects of the invention I work to the grinder and steam to the turbine, parts of the apparatus being shown in elevat1on and other parts in sectional elevation and still other parts in diagrammatic fashion;

Fig. 2 is a graph illustrating one example of regulating effects attainable by the use of the inventlon; and

Fig. 3 is a diagrammatic illustration, in the nature of a sectional elevation of portions of the governing or regulating gear.

It is frequently desirable to drive a plurahty of different machines from the same engine or prime mover, which machines are subject to different conditions or variations of load or other considerations which would render thegoverning of the prime mover in accordance with the requirements of one machine disadvantageous with respect to the op-.

eration of another of the driven machines, For example, in a paper mill, it may be desirable to utilize the same prime mover for driving a wood pulp grinder and an electric generator, which latter supplies current for operation of paper making machines or other uses about the plant. Wood grinders require to be operated at substantially constantload in order to insure a uniform product and minimum power consumption per ton of output. Likewise, it is important that the generator be operated at as nearly constant speed as possible, so as to avoid frequency or voltage variations in its output and resulting disturbances in the operation of machines, such as paper makmg machines, operated by energy suppl ed by the. generator. Moreover, the prime mover isusually designed for most efficient operation at certain speeds, wherefore it is desirable to provide speed regulation for it. Thus, for the proper governing of the apparatus, there are three factors to be'brought into agreement, namely, constant load on the grinder, constant voltage for the generator and constant speed for the prime mover. The attainment of this result involves various difliculties, since the power delivered by the prime mover must conform to the demands of the two machines it drives and must be distributed between them in 15, is fed to the conformity with their r uirements. In prior practice, wood grin ers driven by steam or water turbines usually have been overned by a special speed overnor wherey, in the event of a rise in the s d of the rime mover, resultin from a ro 1n the oad on the grinder, t e load woul be increased by increasing the feed of work to the 'nder. Such arrangements involve certain ossibilities of interference between the fee governor and speed governor of the prime mover. However, even if the feed governor acts at once, a certaln unavoidable delay occurs before its effect on the load becomes appreciable, as it takes a certain time for the feed apparatus to accommodate to the new conditions, particularly if the wood is poorly packed. Conversely, due to the elasticity o the compressed wood, an overload on the grinder is not immediately relieved, but a certain time is required for the grindin away of suflicient wood so as to bring the e ective feed ressure back to the desired load. Substant1al temporary fluctuations in speed are thus unavoidable, with the resulting undesirable efl'ects on the generator, as above mentioned.

The present invention provides a method of governing, and automatic govern ng gear, whereby the load on the grinder s maintained, at all times, equal to the difference between the power output of the prime mover and the power requirements of the enerator. The nature of the invention may e ascertained by reference to the arrangement of apparatus illustrated in the drawing. Here the reference numeral 10 designates the prime mover, in the form of a steam turbine, which drives the generator 11 and the grinder 12, the latter through the medium of reduction gearing 14. The work, grinder 12 by work feed apparatus comprising a piston 16 which is driven by pressure fluid in cylinder 17 to press the work against the grinder. Th1's ressure fluid is supplied from a suitable iiydraulic accumulator, or other source, by the way of the pipe 18, and the effectiveness of its ressure on piston 16 is controlled by a re ating valve 19. The turbine is provide with a speed governor 20 which controls the valve operating mechanism 21, o erable to vary t e supply of steam to t e turbine. This governing and valve 0 ratin gear is illustrated in Fi 3, wherein the in et valve for the turbine 1s desi ated 22. This valve is connected to a piston 24 loaded by a sprin 25 and operating in a cylinder 26 to whic oil is supplied under pressure from a servo line 27 supplied by a pump 28.

As the pressure in line 27 rises, piston 24 is forced upwardly against the pressure of spring 25, thus opening valve 22 to admit more steam to the turbine. The reverse of these operations takes place upon a fall of the ressure in servo line 27. The overnor 20, riven by the turbine, controls t e pressure in servo line 27 through the medium of an adjustable sleeve 20 having an aperture 20" through which pressure 911 may esca from the servo line, the effective area of said a rture being variable bya longitudinal s ifting of sleeve 20 in proportion to the speed variations of the turbine. As the speed of the turbine increases, the centrifu al governor shifts the sleeve to increase t e effective area of the a rture 20", resultin in a relief of pressure m line 27 and a c osing movement of valve 22. In the event of a decrease in the speed of the centrifugal governor, the sleeve is shifted to decrease the escape of pressure oil from the line 27, with the result that the ressure under piston 24 is increased, and va ve 22 given an openin movement. In the arrangement illustrate: the feed regulating valve 19 isalso rendered subject to the pressure variations in servo line 27. This valve 19 is responsive to movements of a lever 29 which may be actuated from a piston 30 operating in a cylinder 31 in communication with servo line 27 behind the piston. A weight 32, which may be varied in accordance with the desired normal feed pressure on the grinder 12, counterbalances the wei ht of the piston and operates against t 0 pressure of the oil in cylinder 31. Movement of the lever 29 is controlled also by a spring 34. As a result, when pressure in cyhnder 31 overcomes the influence of weight 32 and spring 34, valve P ru 19 is given a (:lOSlllg movement, cutting down the effectiveness of fluid pressure in feed cylinder 17, and consequently reducing the load on the grinder 12. It will be observed that this increase in pressure in cylinder 31, and the resulting decrease in feed pressure on the grinder, occur automatically in response to a drop in speed of theturbine.

onversely, an increase in a eed of the turbine results in a decrease o oil pressure in cylinder 31, and opening movement of regulating valve 19 and an increase in load on the grinder.

As pointed out above, there is a third factor which must be taken into consideration in overning the rime mover and the grinder oad, namely, t e volta of the generator, which must be maintained constants.

The generator out ut is rendered effective to influence the regu ating function of valve 19, and through it the operation of the turbine and the grinder feed mechanism, throu h the medium of a rotary magnet'35ihavin'g its coils 36 energized from the mains 37 supplied by the generator 11. This magnet is operably connected with the lever 29 by means of a flexible band 38 which winds on a drum 39 on the magnet, and the maget is so designed that the torque exerted by it is proportional to the power delivered to the mains by the generator; The power of this torque is exerted upon lever 29 in opposition to the oil pressure in cylinder 31, i. e. in a relationship tending to produce an opening movement of regulating valve 19. Consequently, an increase of the generator output tends to produce an increase in the feed pressure in feed cylinder 17, and an increase in the load on the grinder and-a decrease in the speed of the turbine.

The governing of-the prime mover is carried on, therefore, b operation of the apparatus as follows. n starting up the turbine, the valve 40 being closed, a certain oil pressure is produced in cylinder 31, not sufficient, however, to displace piston 30 from its extreme upper position. The valve 40 is then opened, thus applying loadto the grinder, with a resulting decrease in speed of the turbine and rise of pressure in the servo line. When the oil pressure rises sufficiently to overcome the counter-torque exerted by weight 32, the valve 19 will be given a closing movement, thus reducing the load on the turbine with a resultingincrease in speed of the turbine. Thereupon the oil pressure, under regulation of the governor 20, falls, andthe piston 30 takes up a position corresponding to the grinder load,

which is determined by the weight 32. If new a load is applied to the generator 11, the pull of the rotary magnet 35 first causes the valve 19 to open further, whereupon the increased load on the turbine causes the oil pressure in the servo system to rise, resulting in the increase of the speed of the turbine to meet the requirements of the generator,be-

' fore the load on the grinder is appreciably affected. The apparatus now being in the normal operating condition, the operation is kept stable by automatic adjustment of the load on the grinder in response to variations of the generator output or variations of the .turbine speed, which latter is, in turn, subject to the load on the grinder. Thus, the turbine speed generator voltage and the grinder load are maintained constant, and the turbine is operated at its best efliciency.

The conditions are graphically represented in Fig. 2. The ordinates represent the torque on lever 29 and the abscissae the load on the turbine, divided into quarter, half, three-quarter and full load. Curve a represents the torque produced by the oil pressure which opposes the added torques of the counterweight 32 and rotary magnet 35.

These latter are represented by the straight lines I) and c, the former being the constant torque of the counterweight, and the latter the magnet torque which isproportional to a the electrical load. The magnet must be adjusted so that the inclination of 0 is the same as that of the straight part of curve a, which may be accomplished in known fashion by suitable proportioning of resistances and dimensioning of the magnet coils. In

the condition'represented in Fig. 2, it is asbine, and that with full load on the turbine,

the other fifty per cent is absorbed by the generator, which is then also fully loaded. {is the load on the turbine rises from zero to its full value, the oil pressure follows the curve a and exerts a corresponding moment on lever 29, in-opposition to the weight 32. The valve 19-, therefore, will not commence to close until the one-half load point is reached. On applying the load to the generator, the moment due to the oil pressure continues to rise in accordance with the portion of curve a lying to the right of the halfload point. This further increase is balanced, however, by the moment 0 developed by the magnet 35, and the grinder load, which corresponds to the shaded portion between the two curves, will be maintained constant.

What I claim is:

1. The combination with a prime mover and machines driven thereby, of regulating means for varying the load of one of the driven machines, and governin means responsive to speed variations of the prime mover and output variations of the other driven machine for. operatingsaid regulating means.

2. The combination with a prime mover and two machines driven thereby, of a speed governor for the prime mover, a feed regulator for one of the driven machines, and operating means for said feed regulator, said operating means being responsive to the speed governor and the output of the other driven machine.

3. The combination with a prime mover and two machines driven thereby, of governing apparatus responsive to speed variations of the prime mover, feed mechanism for loading one of the driven machines, regulating means for the feed mechanism, and control mechanism for operating the regulating means, said control mechanism being responsive to the governing apparatus and the operation of the other driven machine.

4. The combination with a prime mover and two driven machines having mechanical driving connection therewith, of feed mechanism for loading one of the driven machines, regulating mechanism for controlling operation of the feed mechanism, governing means responsive to speed variations of the prime mover for operating said regulating mechanism, and means controlled bv the other driven machine for operating said regulating mechanism.

5. The combinationwitha prime mover, of a grinder and a generator driven thereby, a speed governor for the prime mover, and aregulator for varying the load on the grinder, said regulator beingl responsive to the speed governor and t generator output.

6. The combination with a prime mover, of a grinder and a generator driven thereby and means governed by speed var at ons 0 the prime mover and output variations of the generator for regulating the load on the grinder.

7. The combination with a steam turbine, of a grinder and generator driven thereby, a governor operated by the turbine, and a regulator for controllin theload on the grinder, said regulator ing responsive to speed variations of the governor and output variations of the generator.

8. The combination with a steam turbine and a machine and a-generator driven thereby, of a governor operated by the turbine, a device operably responsive to variations of the generator out ut, feed mechanism for applying load to t e machine, and regulating means under control of said device and said governor for controlling said feed mechanism.

9. In apparatus of the character described, a prime mover, a plurality of machines driven thereby, means for controlling operating conditions of certain of said machines, and means responsive to operating conditions of said prime mover and certain other of said machines and operable to regulate said control means.

10. In apparatus of the character described, a prime mover, a plurality of machines driven thereby, governing mechanism for said prime mover, means res nsive to operating conditions of certain 0 said mac lines, and means common with res t to governing mechanism and sai firstmeans and operable to provide for said name

regulation of operating conditions of certain. ot e r of said machines. In testimony whereof I have hereunto subscribed my name at Zurich, Switzerland, this 29th day of March A. D. 1927.

RIdHARD SCHNITZER. 

